參數(shù)資料
型號(hào)： 1117I50
廠商： National Semiconductor Corporation
元件分類： 基準(zhǔn)電壓源/電流源
英文描述： Micropower 5V, 100mA Low Dropout Linear Regulator
中文描述： 微5V的，100mA的低壓差線性穩(wěn)壓器
文件頁(yè)數(shù)： 11/21頁(yè)
文件大?。?/td> 535K
代理商： 1117I50
Application Note
(Continued)
The LM1117 regulators have internal thermal shutdown to
protect the device from over-heating. Under all possible
operating conditions, the junction temperature of the LM1117
must be within the range of 0C to 125C. A heatsink may be
required depending on the maximum power dissipation and
maximum ambient temperature of the application. To deter-
mine if a heatsink is needed, the power dissipated by the
regulator, P
D
, must be calculated:
I
IN
= I
L
+ I
G
P
D
= (V
IN
-V
OUT
)I
L
+ V
IN
I
G
Figure 6
shows the voltages and currents which are present
in the circuit.
The next parameter which must be calculated is the maxi-
mum allowable temperature rise, T
R
(max):
T
R
(max) = T
J
(max)-T
A
(max)
where T
J
(max) is the maximum allowable junction tempera-
ture (125C), and T
A
(max) is the maximum ambient tem-
perature which will be encountered in the application.
Using the calculated values for T
R
(max) and P
D
, the maxi-
mum allowable value for the junction-to-ambient thermal
resistance (
θ
JA
) can be calculated:
θ
JA
= T
R
(max)/P
D
If the maximum allowable value for
θ
is found to be
≥
136C/W for SOT-223 package or
≥
79C/W for TO-220
package or
≥
92C/W for TO-252 package, no heatsink is
needed since the package alone will dissipate enough heat
to satisfy these requirements. If the calculated value for
θ
JA
falls below these limits, a heatsink is required.
As a design aid,
Table 1
shows the value of the
θ
of
SOT-223 and TO-252 for different heatsink area. The copper
patterns that we used to measure these
θ
s are shown at
the end of theApplication Notes Section.
Figure 7
and
Figure
8
reflects the same test results as what are in the
Table 1
Figure 9
and
Figure 10
shows the maximum allowable power
dissipation vs. ambient temperature for the SOT-223 and
TO-252 device. Figures
Figure 11
and
Figure 12
shows the
maximum allowable power dissipation vs. copper area (in
2
)
for the SOT-223 and TO-252 devices. Please see AN1028
for power enhancement techniques to be used with SOT-223
and TO-252 packages.
*Application Note AN-1187 discusses improved thermal per-
formance and power dissipation for the LLP.
TABLE 1.
θ
JA
Different Heatsink Area
Layout
Copper Area
Thermal Resistance
Top Side (in
2
)*
0.0123
0.066
0.3
0.53
0.76
1
0
0
0
0
0
0.066
0.175
Bottom Side (in
2
)
0
0
0
0
0
0
0.2
0.4
0.6
0.8
1
0.066
0.175
(
θ
JA
,C/W) SOT-223
136
123
84
75
69
66
115
98
89
82
79
125
93
(
θ
JA
,C/W) TO-252
103
87
60
54
52
47
84
70
63
57
57
89
72
1
2
3
4
5
6
7
8
9
10
11
12
13
10091937
FIGURE 5. Cross-sectional view of Integrated Circuit
Mounted on a printed circuit board. Note that the case
temperature is measured at the point where the leads
contact with the mounting pad surface
10091916
FIGURE 6. Power Dissipation Diagram
L
www.national.com
11
相關(guān)PDF資料
PDF描述
1117IAD Micropower 5V, 100mA Low Dropout Linear Regulator
1117I-50 GIGATRUE 550 CAT PATCH CABLE NO BOOT 30FT GREEN
1117I-AD GIGATRUE 550 CAT PATCH CBL NO BOOT 30FT GR 25 PK
1117I33 GIGATRUE 550 CAT6 PATCH 4 FT, NON BOOT, RED
1117I-33 GIGATRUE 550 CAT6 PATCH 25 FT, NON BOOT, GREEN
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
1117I-50 制造商:NSC 制造商全稱:National Semiconductor 功能描述:800mA Low-Dropout Linear Regulator
1117IAD 制造商:NSC 制造商全稱:National Semiconductor 功能描述:800mA Low-Dropout Linear Regulator
1117I-AD 制造商:NSC 制造商全稱:National Semiconductor 功能描述:800mA Low-Dropout Linear Regulator
1117LC WAF 制造商:ON Semiconductor 功能描述:
1117MA 制造商:NORTH HILLS 功能描述:
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*